10:12:15:18

Chord information

Harmonics	10:12:15:18
Subharmonics	1/(18:15:12:10)
Intervals from root	1/1–6/5–3/2–9/5
Cents from root	0¢–316¢–702¢–1018¢
Step intervals	6/5, 5/4, 6/5
Step cents	316¢, 386¢, 316¢
Prime limit	5
Genus	32⋅5 (45)
Intervallic odd limit	9
Otonal odd limit	15
Utonal odd limit	15
Consistent edos (d ≥ 2)	12edo*, 19edo**, 34edo*, 38edo*, …
* 2 ≤ d < 4; ** 4 ≤ d < 8; *** 8 ≤ d < 16; …

The Ptolemaic minor seventh chord, 10:12:15:18 (1⁄1 – 6⁄5 – 3⁄2 – 9⁄5), is a minor chord found on the third (5⁄4 or III) and sixth degree (5⁄3 or vi) of Ptolemy's intense diatonic scale (Zarlino), perhaps the most common 5-limit diatonic.